Rock drill



J. C. CURTIS `May 14, 1935.

ROCK DRILL ,Filed Ivlay 7, 1934 JOHN c. amer/5 Patented May 14, 1935 i UNITED N ,STATES PArEr orties 2,001,127l l y Roon DRILL `John C. Curtis, Garfield Heights; Ohio, assignor to The Cleveland Rock Drill Company, Cleveland, Ohio, a corporation of Ohio Application May 7, 1934, seriarNd. 724,293

7 Claims.

`This invention relates` broadly to huid actuatedV rock drills, but more particularly to the valvular mechanism for fluid actuated rock drills oi the v the cylinderto the bottomof the drilled hole being drilled, affording cleaning thereby an efficient hole device without increasing the motive fluid consumption of the machine.

` Other objectsv and advantagesmore or less4 ancillary to the foregoing reside 'in the speciiic concylinder.`

the valve `against, relative rotation tatably `mounted Within struction and aggroupment oi the elements peculiar tothis structure, as` will become apparent from amore complete examination of this specincation. y

` In the accompanying drawing illustrating the invention,

Figure 1 is a longitudinal sectional view of a ,rock drill embodying the invention.

Figure 2` isan enlarged longitudinal sectional View of the valvular 'mechanism shownin .Figure 1, illustrating thevalve positioned for permitting the admission of the pressure into one end of the Figure 3 is a View similar to FigureZ illustrating of the pressure fluid into the other end of the cylinder.

Referring to the drawingin whichlike symbols designate corresponding parts` ythroughout the several views, `l represents the cylinder of a rock piston il formed with asplined stern l2. Secured within the front end of the cylinder l there is a front bushing i3 accurately machined to slidably receive the stem I2, the

the iront bushing I3,

` and extending into a front housing I5. Slidably |8,\-| 9, and 2U. `Secured within thefrear end portionoiv the valve blockv Il, there is a valve bushing 2l formed with a mounted `Within the chuck I4, there is the shank IG` of a tool implement upon which the piston Il is capable of delivering its blows.` r

Secured within the` back end of the cylinder llLthere isa valve block Il formed with a plurality of intercommunicating internal chambers positioned for permitting the admission' latter being connected` with a chuck irl ro-` through in press t engagement faces capable of engagement with two opposed annular valve seats Zland 28, g ing into the valve chamber i8 while the latter isl a part of the valve cap 2.7i.` Extending from the inner end of the disc 25, the valve member 24 is formed with a sleeved portion 29 provided,.in`

the `former protrudtermediate itsends,A with a relatively large annular` external groove Sil and a relatively small internal flange 3 l, the latter being slidably mountedk on the'sleeved portion 22 of the valve bushing 2 l.y Toprovide better guiding and Wearing surfaces,` the left inner wall 'oi'the valve sleeve 29 is slidablyv engageablewith the valve bushing 2l extending therein, thus dening with the valve innerhahge 3l a chamber 32. Similarly, `the right inner wall, of the'valve sleeve 29 is slidably engageable with a protruding portion 3,3 of` the valve cap 23, thus defining with the valve inner nange 3l a chamber" 3ft.` Leading from the valve sleeve groove 330 into the chamber it, there is a restricted port 35, while a similar port 35 is provided through the disc` 25. The front or right end portion of-the interior of the cylinder i is capable of constant communication with the chamber l 9 through a plurality of iront inlet passages 3l, while theback or leftV end portion of the interior of the cylinder lll is capable of communication with the chamber I8. through a plurality of rear inlet passages 38.y Leading from the interior of the cylinder lil to the atmosphere, `there is an exhaust port 39. Again leading from the interior of the cylinder, there is a port fit1 opening into the chamber 2D, the latter being constantly connected with the ychamber 32 through a plurality of passages 4l.

` Secured to the end of the cylinder by a pair of bolts, there is a back headrlli. having rotatable therein athrottle` valve d3 formed with a centrally disposed port lil connected to the exterior of r the throttle valve through a radially disposed' port t5. Disposed between thevalve block l1 and the` back head d2, there is the common rotation. mechanism comprising a ratchet ring 4t, and rie stem 4l, the latter extending into the cylinder l0 the valve bushing 2l for cooperation with the piston i2 in the well-known manner. Interposed4 between the ratchet ring 4B and the back head d2, thereis a ratchet ring bearing plate48 formed with an enlarged annular groove 49` capable of communication with the throttle valve port 45': through an oriiice 50, and with the valve block chamber I8 through a plurality of ports 5|.

Leading from the throttle valve 43 to the shank i6 of the tool implement, there is a port 52 in constant communication with the outer end of the valve sleeve portion 29 through a port 53 and annular groove 54.

The operation of the machine is as follows: Assuming the valve member 25 to be positioned as illustrated in Figs. 1 and 2 with the throttle valve positioned as illustrated in Fig. 1, pressure fluid from the throttle valve is admitted into the annular groove 49 through the throttle valve passage 45 and port 50. From the groove 49, pressure fluid is admitted into the valve block chamber i8 via the plurality of ports 5l, to act on the left side of the valve disc 25 for holding the valve on the valve seat 2S. In this instance, the marginal wall of the disc 25 is engaging the inner wall 25 of the chamber i8, preventing thereby the flow of the fluid around the disc. From the left side of the valve disc 25 the pressure fluid is gradually admitted on the right side of the disc through the restricted port 36, reducing thereby the effective holding area on the left side of the disc to an area substantially equal to the area of the valve seat 2l. Simultaneously, the pressure fluid is also admitted into the chamber 34, through the restricted vport 35, to act on the right side of the inner flange 3l tending to shift the valve toward the left. However, the eiecting holding area on the left side of the valve disc 25 is large enough to resist the action of the pressure fluid on the inner valve flange 3 I. From the chamber i8, the pressure fluid is free to flow into the chamber i9 via the clearance existing between the inner wall of the valve seat 2l and the valve groove Sli, and from the chamber I9 into the front end of the cylinder It through the ports 31. Pressure uid admitted into the front end of the cylinder will act on the piston il to drive the latter toward the left. During the leftward movement of the piston, the atmosphere within the left end portion of the cylinder compressed by the piston, will act on the front portion of the valve disc exposed thereto through the ports 38, thus tending, together with the pressure fluid acting on the left side of the inner flange 3i, to shift the valve toward the left. The valve, however, will not shift until the piston finally uncovers the exhaust port 39, permitting thereby the pressure fluid in the front end of the cylinder to exhaust to atmosphere and thereby causing a drop of pressure on the left side of the valve disc 25.

During the shifting of the valve, the marginal wall of the disc 25 does not leave the inner wall 26 of the chamber I8 previous to the engagement of the inner end of the sleeved portion 23 with the inner wall of the valve seat 21, preventing thereby the simultaneous ilow of the pressure fluid into the front and rear end of the cylinder through the passages 31 and 38.

When the valve is positioned as illustrated in Fig. 3, the pressure fluid admitted in the chamber I8 is free to flow around the disc of the valve to act on the right side thereof for holding the valve in its rearward position. From the right side of the disc, the pressure fluid is admitted into the left end of the cylinder through the ports 38 to drive the piston to the right or against the shank I6 of the tool implement. The pressure fluid previously admitted in the chamber 34 for acting on the right side of the valve inner port 53 and flange 3l is now free to flow to the bottom of the hole being drilled via the chamber I3, valve groove 38, annular recess 54, ports 53 and 52 and the interior of the hollow tool implement IS.

During the rightward stroke of the piston, the latter will first uncover the port All, thus admitting pressure on the left side of the inner valve flange 3l or into the chamber 32 via the port 4U, chamber 20 and ports 4l, tending thereby to shift the valve toward the left. However, the effective holding area of the right side of the valve disc 25 being greater than the area on the left side of the inner flange 3l, the valve will not shift until the piston Il uncovers the exhaust port 39, creating thereby a drop of pressure on the right side of the valve disc 25 permitting the shifting of the valve. During the rightward stroke of the piston, when the latter covers the exhaust port 39, the atmosphere, and possibly some motive fluid under relatively low pressure remaining in the right end of the cylinder, is compressed by the piston during its travel toward the right end of the cylinder. Heretofore, no provisions were made to relieve such compression, which obviously will retard the forward movement of the piston and consequently will prevent the latter to strike the tool implement with all the power generated during the forward stroke of the piston. In the present construction, the iluid within the right end of the cylinder normally compressed by the piston, is free to exhaust therefrom through the port 3l, chamber i9, valve groove 30, annular recess 54, ports 53 and 52 to be admitted to the end of the shank it from where it will flow through the port formed in the tool implement to the bottom of the drilled hole for cleaning the latter. In this manner, the fluid compressed by the piston is not only permitted to exhaust from the front end of the cylinder, but is utilized for blowing the hole being drilled, affording thereby an efficient method and device for removing the chips from the bottom of the hole without increasing the motive iluid consumption of the machine. When the piston finally uncovers the exhaust port 39, the valve will trip in the position shown in Figs. 1 and 2 thus completing the cycle.

When it is desired to admit a supplemental amount of pressure fluid to the bottom of the drilled hole, the throttle valve may be rotated ,2

to permit the communication of the throttle port [i5 with the port 52, preventing thereby the admission of the pressure fluid in the chamber I8. In this instance, the pressure fluid flowing through the port 52 is also admitted on the outer end of the valve sleeved portion 29 tin'ough the similar recess 561. Pressure fluid thus admitted on the valve will have no other consequences than simply maintaining the valve in the position shown in Figs. 1 and 2.

Although the foregoing description is necessarily of a detailed character, in order to completely set forth the invention, it is to be understood that the specific terminology is not intended to be restrictive or confining and it is to be further understood that various rearrangements of parts and modification of structural detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a hollow tool implement slidable within the front end of the machine. of a fluid actuated Valve into the end portions of end portion, and

` in time relation with `said piston for controlling the admission of thepiston actuating pressure fluid into said cylinder, a passage controlled by said valve member being open thereby during the stroke of said piston in one direction for admitting compressed :duid from the interior of said cylinder to the bottom of thehole being drilled via said hollow tool implement, and being closed by said valve member during the stroke of said piston in the other direction.

2. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, of a hollow tool implement slidable within the front end of the machine, of valve controlledpassages for alternatively admitting pressure uid said cylinder for actuating said piston, of an exhaust port through which the pressure fluid admitted into said cylinder may exhaust therefrom, one end portion of said cylinder constituting a cushion chamber wherein the air remaining therein subsequent to the exhaust of the pressure fluid therefrom through said exhaust port is normally compressedv by said piston during its stroke toward said one end portion, means for admitting said compressed air via `the interior of said tool implement to the bottom of the hole being drilled for cleaning the latter during the stroke of said piston toward said one means for closing said cushion chamber from said tool implement during the movement of sai-d piston away from said one end portion.

`3. In a iiuid actuated rock drill, the combination of a cylinder having a piston reciprocable therein, a hollow tool implement slidably mounted within the front end of the rock drill, a valve block, front and rear inlet passages leading from said valve block to the end portions of said cylinder, a valve reciprocable within said valve block for controlling `the flow of the pressure fluid through said inletv passages, said valve comprising a disc having a sleeve extending: therefrom, an inner flange within said sleeve, the opposed sides of said disc and ange constituting pressure areas on which pressure fluid may be admitted for actuating said valve, said valve being shifted in one position by the pressure fluid constantly admitted on one side of said disc and intermittently admitted on the corresponding side of said inner flange, the shifting of said valve in the other direction being responsive to the compression from the rear of the cylinder intermittently admitted on the other side of said disc- `and by the pressure fluid intermittently admitted on the corresponding side of said inner iiange,

and means for admitting and exhausting pressure 'fluid to and from the sides of said disc and flange, said means including one passage for exhausting the pressure from one side of said iiange to the bottom of the hole being drilled for cleaning the latter via the interior of said hollow tool implement.

i 4,. In a rock drill, the combination of, a cylinder having a fluid actuated piston reciprocable therein, the end portions of said cylinder constituting forward and rearward pressure chambers within which Huid is admitted for actuatingsaid piston, a hollow tool implement slidably mounted within the front end of the machine, and means whereby fluid from said forward pressure chamber is admitted to Said tool implement during a portion of the stroke of said piston toward said last mentioned chamber, said means preventing fluid from said forward pressure chamber to be admitted therefrom to said tool implement after the reversal of said piston stroke. Y

` 5. In a rock drill, the combination of a cylinder having a fluid actuated piston reciprocable therein, the air within one end portion of said cylinder being normally compressed therein by the piston during the stroke thereof toward said one end portion, a tool implement slidably mounted within the front end of the machine, and means whereby said air compressed within said one end portion of the cylinder is admitted to said tool implement during a portion of said piston stroke, said means preventing said compressedair from said one end portion of the cylinder to be admitted therefrom to said tool implement during the stroke of said pis-ton away from said one end portion.

6. In a rock drill, the combination of a cylinder` having a uidactuated piston reciprocable therein,` the end portions of `said. cylinderl constituting forward and rearward pressure chambers within which fluid is admitted for actuating said piston, a hollow tool implement slidably mounted within the front end of the machine, a iiuid conveying passage aiording the communication of said 'forwardpressure chamber with said tool implement, and a fluid actuated .valve movable in open position relative to said passage during a portion of the stroke of said piston toward said last mentioned chamber, and in a closedposition relative to said passage during the primary majorportion of said piston stroke toward the other of said pressure chambers.

having a fluid actuated in, the end portions of said cylinder constituting forward and rearward pressure chambers within which fluid is admitted for lactuating said piston, an exhaust port controlled by said piston through which the fluid from said chambers may exhaust, a hollow drillsteel slidably mounted within the front end of the machine, a fluid conveying passage aording the communication of said forward pressure chamber with said tool implement, and automatically operated valve means 7. In a rock drill, the combination of a cylinder piston reciprocable there-y movable to a position to open said passage during a portion of the stroke of said piston toward said forward pressure chamber and to a position to close said passage during the travel of said piston oversaid exhaust port on its way toward said rearward pressure chamber.

. JOHN C.CUR'I'IS.v 

